Creeper.



P. N. BIEROE.

GREEPER.

APPLICATION FILED JAN. 13, 1914.

Patented Feb. 16, 1915.

3 SHEETS-SHEET l.

"HE NORRIS PETERS ($0., PHOTO-LITHQ. WASHINGTON. D, C.

WWW.

F. N, BIEROE.

OEEBPER.

APPLICATION FILED JAN.13. 1914.

Patented Feb. 16, 19151 3 SHEETS-SHEET 2.

"HE NORRIS PETERS c0 PHOTO'LITHQ. WASHINGTO! P. N. BIEROE.

OREEPER.

APPLICATION FILED JAN. 13, 1914.

Patented Feb. 16, 1915.

L 1 1 gm 3 SHEETS-SHEET 8.

i in E NORRIS PETERS 60., PHOTC-LITHQ. WASHINGTON, D. (L

FRED N. BIERGE, OF CINCINNATI, OHIO.

CREEPER.

riaarie.

Specification of Letters Patent.

Patented Feb. 16, 1215.

Application filed January 13, 1914. Serial No. 811,843.

To all whom it may concern Be it known that I, FRED N. BIERCE, a citizenof the United States, and a resident of Cincinnati, in the county ofHamilton and State of Ohio, have invented certain new and usefulImprovements in Creepers, of which the following is a specification.

My invention relates to means for laying of cables in conduits, and hasfor its object the facilitation of threading a line through the conduit,preparatory to pulling the cable into the conduit.

My invention consists in the parts and in the details of constructionand arrangement of parts as will hereinafter be more fully described andclaimed.

In the drawings: Figure 1 is a general side elevation of my invention inone of its positions during its operation; Fig. 2 is a similar view ofthe same in another position; Fig. 3 is a similar view of the device inretracted condition for withdrawal from the conduit where necessary, asin case the device meets with an impassable obstruction; Fig. 4 is alongitudinal vertical section of the extreme forward and rearward partsof the device, with the middle part broken away for lack of space; Fig.5 is a longitudinal transverse section of the same but with the stem andthe springs and collars thereon shown in full plan; Fig. 6 is alongitudinal vertical section of the middle part of the device; Fig. 7is a longitudinal transverse section of the same, with the stem and thecollars and springs thereon shown in full plan; and Fig. 8 is a detailof part of one of the shoes of modified construction.

The stem 1 is tubular and has the front head 2 rigidly secured to itsfront end and the stem yoke 3 rigidly secured to its rear end. A rearhead i slides on this tubular stem 1 and has a rearwardly extendingframe comprising side parts 5 flanking the stem and joined by a bracket6 at the rear end, which bracket also has a bearing on the stem 1, sothat the entire structure composed of this rear head 4 and its frame mayslide on the stem together, all preferably being formed integral. Fixedto this bracket (3, at opposite sides, are plates 7 which have threadedrods 7 that extend rearwardly and upon which an end piece is adjustablyheld by nuts 8, which end piece may also slide on the stem 1. Directlyto the rear of the bracket 6 is the pulley-block 9 with these plates 7flanking it, this pulley-block being also slidable on the stem 1 andheld up against the bracket 6 by a helical safety spring 10 whichsurrounds the stem 1 and is compressed between this block 9 and the endpiece 8.

The front head 2 has the arms 11 and 12 pivoted to it at opposite sides,each arm extending over to the respective opposite side of the device,and said arms being of bifurcated construction so that each may extendthrough the other where they cross at the middle of the device. Each armcarries a shoe 13 adapted to bear against the inner side of the conduit.As shown in all of the illustrations except Fig. 8, the shoe ispreferably composed of wood, presenting the ends of its fibers againstthe wall of the conduit so that efficient frictional contact is madewith the wall. These arms 11 and 12 incline rearwardly across thedevice, so that when a backward pull is exerted on the head 2 these armswill tend to assume positions at right angles across the conduit, thuscrowding their shoes against the walls of the conduit, so that anincreased pull on the head results in an increased frictional contact ofthe shoes, and consequently these arms with their shoes will hold allthe tighter the more the pull is increased. To normally hold the shoesout against the walls of the conduit, the arms 11 and 12 have togglelinks 1 1 and 15, respectively, pivoted to them on each side of thedevice and pivoted to a forward toggle-head 16, on both sides of saidhead, while the head is slidable on the stem 1 and has a helicalgripping spring 17 around the stem and compressed between thetoggle-head and a collar 18 fixed on the stem. The rear head 4 is in asimilar manner provided with arms 19 and 20 having shoes 21 hearingagainst the walls of the conduit and normally held outward by togglelinks 22 and 23, respectively, on both sides of the device which arepivoted to a rear toggle-head 24- on both sides thereof, whichtoggle-head slides on the stem 1. and has a helical gripping spring 25around the stem and compressed between the togglehead and the bracket 6of the frame which the rear head 4 has.

The pulley block 9 has studs 26 extend ing out from opposite sides, uponwhich grooved pulleys 27 are rotatably mounted, the sides of the block 9preferably being recessed to receive these pulleys 27, and having plates28 secured over the pulleys by screws 29 with the studs 26 extendingthrough the plates and receiving washers 30 with cotter-s 31, which thussupplement the screws 29 in holding the plates 28 in place and confinethe pulleys 27 to the studs. At one side of the device, a cable 32 hasone end fixed in the stem yoke 3 at one side at the top thereof andpasses forwardly and down around the pulley 27 on that side and backwardand loosely through an opening 33 in the lower part of the stem yoke 3on that side. At the other side of the device another cable 34 has oneend fixed in the stem yoke 3 at the bottom and passes forward and uparound the pulley 27' on that side and backward and loosely through anopening 35- in the upper part of the yoke on that side. These two cables32 and 34, after passing loosely through the yoke 3, extend a sufficientdistance backward and have their other ends fixed in a cable yoke 36which has an eye 37 receiving a snap hook 38 on the end of a cord 39.

A long helical motor spring 40 is confined between the rear side of therear end piece 8 and the front side of the safety collar 41. This collaris held forward by a helical safety spring 42, this safety spring 42being around the stem and compressed between the collar 41 and the stemyoke 3. The safety springs 10 and 42 are much stronger than the motorspring 40,v and will yield only under conditions later tobe described.

With the parts arranged as above de scribed and in their positions asillustrated in Fig. 1, which is the condition of the device as it isplaced in the conduit, the gripping springs l7 and 25 spread the arms onthe heads 2 and 4 outward, with the shoes gripping the walls of theconduit, while the motor spring 40 is holding the rear head 4 and itsassociated parts forward on the stem. Now, when a pull is exerted on thecord 39, which extends backward out of the end of the conduit, thecables 32 and 34 will act around the pulleys 27 and upon the stem yoke3, with the rear head 4-providing the stationary reaction, with theresult that the entire stem and the front head 2 and associated partsthereon will be pushed forward, compressing the motor spring 40, sothat, at the completion of this operation,

the parts will be in the positions indicated in Fig. 2. It will beunderstood that the gripping spring 17 has yielded slightly when thehead 2 travels forward so that the. shoes 13 freely slide along thesurfaces of the walls of the conduit, but as soonas the forward head 2stops the shoes 13 will immediately grip the walls of the conduit againunder the pressure of the spring 17 and then when. the operator ceasesto pull on the. cord 39 the motor spring 40 will expand and push thehead 4 and the entire structure associated therewith forward on the stem1 until it again reaches a position, relative to the forward head 2,like that shown in Fig. 1. This latter action will have taken place withthe forward head 2 having its arms gripping with their shoes andproviding the stationary reaction for the action of the motor spring 40in pushing the rear head 4 forward; and the shoes 21 on the arms of thisrear head 4 will slide along the walls of the conduit, with the grippingspring 25 yield ing slightly to permit this. Then, as soon as this rearhead 4 stops, the shoes 21 will again grip the walls of the conduit; andupon the next pull on the cord 39 the stem 1 and forward head 2 andassociated parts will again be extended forward and the operationrepeated.

From the foregoing it will be seen that it is necessary only to repeatthe alternate pulling and slacking of the cord 39 to cause the device tocreep forward through the conduit; and when the device has reached theother end of the conduit and been withdrawn therefrom by an operator atthat end the cord 39 will be threaded through the conduit and will beavailable for drawing the fish-wire through the conduit which in turnwill be used for drawing the cable through the conduit. to have but theone cord 39 pass through the conduit; and the device can be operatedwith one hand, since there is but one cord to manipulate.

Should the device meet an obstruction which cannot be removed by thepulling forward of the stem and front head because it over-taxes eitherthe operators strength or the strength of the cord 39, it becomesnecessary to withdraw the device back through the conduit and to takesome other measure for removing the obstruction.

In order to withdraw the device, it is necessary that all of the shoes13 and 21 be retracted from the walls of the conduit, since, as abovedescribed, when these shoes grip the walls of the conduit, it isimpossible to draw the device backward, because the shoes hold moretightly the stronger the backward pull upon them. It is to provide forthis contingency that the pulley block 9 is made separate from the rearhead 4 and its frame, and held up thereagainst by the safety spring 10as above described; and it is also to provide for this that the safetycollar 41, to the rear of the motor spring 40, is held up by the safetyspring 42 as was described. Thus, the pulley block 9 has spreaders 43vfixed to it at the top and bottom by screws 44, the plates 7 beingbifurcated for connection to the bracket 6, as hereinbefore described,thus permitting these spreaders 43 to be secured to the pulley block.These spreaders 43 extend forwardly along the top and bottom members Itis thus necessary 5 of the frame, and near the front end of the framefiat springs 45 are fixed to the frame close to the head 4 and extendrearwardly along the top and bottom members 5, and outside the spreaders43 with pins 46 extending in through slots 43 in the spreaders andthrough openings 47 in the frame members, 5 and engaging with acollapsing collar 48 that is slidable on the stem 1. A helicalcollapsing spring 49 around the stem 1, is confined between thecollapsing collar 48 and the rear side of the rear head 4. The spreaders43 have their ends inclined inwardly around inclined shoulders 50 on theframe members 5, so that if these spreaders are pulled backward alongwith the pulley block 9, they will ride up on the shoulders 50, spreadthe flat springs 45, Withdraw the pins 46, and release the collapsingcollar 48 under the action of the collapsing spring 4-9. The collapsingspring 49 is made much stronger than the gripping spring 25, and thisspring 25 is thus overpowered and completely compressed, so that thearms 19 and 20 are drawn inward, and their shoes 21 cannot make grippingengagement with the walls of the conduit.

The safety spring 42 bears the same re-' lation to the forward head 2and its arms 11 and 12 that the safety spring 10 does to the rear head 4and its arms 19 and 20. Thus, the safety collar 41 has a transverse pin51 which passes through longitudinal slots 52 in the walls of thetubular stem 1 and carries, inside the stem, a hub 53 in which the rearend of the connecting rod 54 is held by the pin 51. The entirestructure, comprising this rod, the hub, the pin and the collar, isslidable along the stem 1 to the extent allowed by the length of theslots 52. Normally, this structure is held forward by the safety spring42, and the forward end of the connecting rod 54, near the head 2 at theother end of the device, carries a wedge 55 which fits inside the stem 1and, when held forward by the spring 42, this wedge has a shoulder undera spring hook 56 which is fixed in a plug 57 in the front end of thestem 1 and extends backward and then laterally outward through anopening 58 in the wall of the stem 1, where it engages with the rearside of the collapsing collar 59, between which collar and the rear sideof the head 2 is compressed the helical collapsing spring 60. The springhook 56 tends to spring inwardly of the stem and release the collapsingcollar 59 and collapsing spring 60, and this collapsing spring 60 ismuch stronger than the gripping spring 17, and if it is released it willoverpower and completely compress the gripping spring 17, and the armswill be drawn inward, and their shoes 13 cannot grip the walls of theconduit.

From the foregoing description of the safety collapsing devices for bothrear and forward heads, it may be understood that when the device meetswith an obstruction which offers sufficient resistance, a continued andstronger pull on the cord 39 will release both forward and rear heads.Now, suppose the forward head to be traveling forward from the positionshown in Fig. 1 to that shown in Fig. 2 with the rear head gripping theconduit walls, and that at any part of its forward travel this forwardhead meets with an obstruction in the conduit: If the obstruction isloose and is light enough, or if it is only lightly attached to thewalls of the conduit, neither of the safety springs 10 or 42 will yield,and the pull on the cord 39 will cause the forward head to dislodge theobstruction and push it along in the conduit. In fact the gripping powerof the device is found in practice to be such that it is possible todislodge any obstruction not so heavy or tightly fixed as to causebreakage of the cord The prevention of breakage of the cord 39 is themost important purpose of the safety collapsing and releasing devices.Thus, in the illustration above given, the safety springs 10 and 42 aremade of such stiffness relative to the strength of the cord 39 that awide margin of safety is assured, and when the forward head 2 meets theobstruction it will continue to act to dislodge the obstruction only tothe extent that the safety spring 10 is able to resist backward movementof the pulley block 9, which as will be seen from the descriptionhereinbe fore given, must provide the stationary reaction for the actionof the cables 32 and 34. in pulling the forward head 2 forward. If theobstruction offers sufficient resistance, and the safety spring 10 isthus overcome and permits the block 9 to move bacluvard, the collapsingcollar 48 will be released, owing to the spreading of the flat springs45 and the withdrawal of the pins 46, and the collapsing spring 49 willovercome the gripping spring 25 as before described, whereupon the arms19 and 20 of the rear head 4 are released from their gripping contactwith the conduit walls. It then remains to render the forward headinoperative, since although. it was traveling forward, if it isattempted to drag the device backward the arms 11 and 12 of the forwardhead will immediately grip the conduit walls and prevent this.Therefore, the operator continues to pull backward 011 the cord 39,which action will now compress the motor spring 40 by pulling the entirerear head 4 and pulley block 9 and the other parts backward along thestem 1, which is now held stationary by the gripping of the arms of theforward head 2. When this motor spring 40 has been completelycompressed, the pull on the cord 39 will be positively exerted on thesafety collar 41, which will move backward with its pin 51 sliding inthe slots 52 in the stem 1, the safety spring 42 being overcome andcompressed by this action, and the wedge being withdrawn from under thehook 56, which hook will spring inwardly on the stem and withdraw itslateral part from behind the collapsing collar 59, allowing thecollapsing spring to overcome the gripping spring 17, and withdrawingthe arms 11 and 12 from their operative positions. The device will thenassume an appearance somewhat as shown in Fig. 3, since the motor spring40 will then force the stem and forward head backward in the device, andthe entire device will be dragged backward bodily by the pull of thecord 39 thereon, and the motor spring 40 will incidentally expand and beonly slightly compressed by the :reactiondue to the weight of the deviceas it :is dragged backward through the conduit. It will thus beunderstood that, not only is a very simple means provided for releasingthe device when it meets with an obstruction, but the safety releasingor collapsing mechanism is entirely automatic in its prevention ofbreakage of the cord 39, since it is necessary only to assure that thecord 39 is always of sufiicient strength to successively compress thesafety springs 10 and 4:2, and the weight of the obstruction, or thetightness with which it is lodged, can offer no danger of breakage ofthe cord 39 as long as the safety springs .10 and 42 are weak enough toyield before suflieient strain has been imposed upon the cord 39 tobreak it. The importance of thus safeguarding the cord 39 will beapparent, for if this cord breaks with the device far into the conduitthe device will not only be difficult to reach fromthe end of theconduit, but it will have all of its arms tightly gripping the walls ofthe conduit and it will be necessary to per form the tedious and almostimpossible op eration of engaging some instrument either with the partof the cord left attached or with the yoke 36 or its eye 37. With thesafety automatic collapsing device there need be no occasion for thusfishing the device out of the conduit as long as care is taken that thecord 39 is always strong enough to compress the safety springs 10 and42, one at a time. Of course where the obstruction is such that thedevice must be collapsed and released and drawn backward out of theconduit as above described, it willbe necessary to gain access to theobstructed part of the conduit by suitable means well known in the art,and remove the obstruction. The length of cord 39 which has passed intothe conduit will afford an indication of the exact location of theobstruction along the conduit. It is not necessary for the device tomeet with an obstruction however, in order to collapse it.

Thus, should it be desired to withdraw the device at any time afterhaving started it through the conduit, as for instance, if it should befound that it has been started through the wrong conduit, it is merelynecessary to exert a continued and stronger pull on the cord 39 afterthe front head 2 has been fully extended forward andithe motor spring t0has been fully compressed. In this condition the two safety springs 10and 42 will be directly opposed to each other and they will both yieldand release the collapsing springs of both heads so that the arms ofboth heads will be retracted practically simultaneously. It is generallydesirable that the safety spring 42 for the front head be somewhatstronger than the safety spring 10 of the rear head so that this latterspring will yield first under any of the above conditions.

The strength of the safety spring 10 of the rear head will determine thepower of the device for moving an obstruction, since the obstruction ismoved by the front head traveling forward with the pulley block 9 of therear as the stationary reactive part held forward by said safety spring10. It is for this reason that I prefer to make the rear end piece 8adjustable along the rods 7. This adjustment enables the operator toincrease the resistance of the safety spring 10 in cases where hisjudgment so dictates.

When the device has been collapsed and drawn backward out of the conduitfor any reason, it may be set into operative condition again by pushingthe toggle head 2 t forward, carrying the collapsing collar 4-8 forwardwith it until the collar passes between the pins 46, which, with theirflat springs 45 yield outward and then snap back behind the collar 48again, confining the collapsing spring 49 as before and leaving thegripping spring 25 free to act upon the arms 19 and 20 through thetoggle. To facilitate this, the collapsing collar 4-8 has slight bevels61 on its sides where the pins must slide over it and the pins havetheir ends also slightly beveled as shown. This operation will set themechanism of the rear head 4-. Then, to set the mechanism of the forwardhead 2, the safety collar 41-1, at the rear end of the device, is pushedback against the pressure of the safety spring 42, to withdraw the wedgefrom under the hook 06 at the front end, since the wedge will haveimmediately been moved forward after the collapsing of the mechanism ofthe front head. When the hook 56 has sprung back, the toggle 16 may bepushed forward, pushing the collapsing collar 59 forward until thiscollar has passed the lateral part of the hook, whereupon the safetycollar 4-1, at the rear end of the device, is released, causing thewedge 55 to press the hook up be hind the collapsing collar 59, whichwill all thus hold the collapsing spring 60 compressed and leave thegripping spring 17 again free to act on the arms 11 and 12 through thetoggle. The toggle head 24-. is provided with recesses 62 to fit aroundthe pins -16 when the toggle head is pushing the collapsing collar 48forward and the pins are coming behind the collar. Likewise the togglehead 16 has a recess 63 which fits around the lateral part of the hook56 as it is forced behind the collapsing collar 59 when this toggle headis pushing this collar forward. These setting operations may be quicklyaccomplished by the operator without assistance, and the device may beimme diately started through another one of the conduits, where severalconduits are run parallel.

By providing the cord 39 with the snap hook 38 hooking into the eye 37on the yoke 36, the cord may be quickly attached for running through theconduit, then detached at the other end and the device may beimmediately connected to another cord at that end for running backthrough another one of the conduits, if several conduits are runningparallel. As I have constructed the device, it will travel through theconduit at the rate of about one foot per second with ordinary exertionon the part of the operator in alternately pulling and releasing thecord 39, and it may be stated that obstructions offering resistance upto or lbs. may be readily pushed forward through the conduit, not onlyowing to the lightness of the device itself, which thus leavespractically all of the power of the operator to be used in suchinstances, but owing to the firmness with which the device grips thewalls of the conduit and thus affords the stationary reaction necessary,and to the extremely smooth and direct application of the power to thedevice. Thus, although the rear head is pushed forward merely by thecomparatively light action of the motor spring 40, the forward head isalways pushed forward by the positive exertion of the power of theoperator, with the rear head firmly gripping the conduit walls andproviding the stationary reaction. Wherever obstructions are movable bythe device, they'will always be moved by the front head. Where theobstruction consists of mud or similar substance, the shoes of the fronthead will clear paths for the shoes of the rear head, the

would be unable to pass, owing either to obstruction or to sharpness ofthe bend, it would be impracticable to draw the sheathed cable through,on account of the risk of damaging the sheathing of the cable by drawingit past such obstructions or bends.

As shown in Fig. 8 a steel calk 6% is fastened in the end of the arm,which is provided with a solid end 65, whereas with the wooden shoes 13and 21 the arms 11 are made in separate parts and riveted togetherthrough the wooden shoes. This calk 64 may be hardened, and when wornmay be removed and a new one inserted. The choice between the woodenshoe and the steel calk or any other suitable gripping means willgenerally depend upon the nature of the material of which the conduit ismade. It will also be understood that other details of the device may bemodified as circumstances may dictate, and therefore, while I haveillustrated and described certain constructions specifically, I do notwish to be understood as being limited precisely thereto, but

What I claim as new and desire to secure by Letters Patent is:

1. In a creeper, gripping mechanisms, a single tension element, meanswhereby successive tensions exerted on said element cause the mechanismsto grip alternately and cause each mechanism to travel with respect tothe other while the other is gripping, and means whereby increasedtension renders both of said mechanisms inoperative.

2. In a creeper, gripping mechanisms, each comprising springs causing itto operate, means acting by a succession of tensions to alternatelycause each mechanism to travel while the other is gripping, anotherspring to each mechanism normally held inoperative, and means wherebyextra tension releases these other springs to over-- power the springsthat cause the mechanisms to operate.

3. In a creeper, gripping mechanisms, means acting by successivetensions to alternately cause each mechanism to travel while the otheris gripping, a gripping spring to each mechanism, causing it to grip, acollapsing spring to each mechanism, and means to each mechanism holdingthe collapsing spring normally inoperative, a safety spring for eachmechanism, and operative connection from each safety spring to therespective collapsing spring, whereby when the safety spring yields, thecollapsing spring becomes operative and renders inoperative therespective gripping spring, said safety springs yielding upon extratension on the aforesaid means.

4. In a creeper, a forward head, a stem fixed thereto and extendingrearwardly therefrom, a rearward head on the stem and movable relativeto the stem and .forward 1d, a motor spring on the stem acting rorwardlyagainst the rearward head, tension means connected with the rearwardhead and extending from said rearward head to have tension applied toit, whereby it will cause relative movement of the stem and rearwardhead against the action of said motor spring, a pair of arms on eachhead, each arm on the head being pivoted at one side of the head andrearwardly inclined across the other arm and past the point where saidother arm is pivoted on the other side, and means to each head yieldablyforcing the arms forward from their rearward inclinations,

5. In a creeper, a forward head, a stem fixed thereto and extendingrearwardly therefrom,a rearward ead. an the stem and movable relative tothe stem and forward head, a motor spring on the stem acting forwardlyagainst the rearward head, tension means connected with the rearwardhead and extending from said rearward head to have tension applied toit, whereby it will. canse relative movement of the stem and rearwardhead against the action of said motor spring, a pair of arms on eachhead, each arm on the head being pivoted at the side of the head andrearwardly inclined across past the pivoting of the other arm on theother side, a toggle head on the stem for each pair of arms, togglelinks connecting the toggle head with the respective arms, and grippingsprings pressing the toggle heads forward.

6,. In a creeper, a forward head, a stem fixed thereto and extending'rearwardly therefrom, a rearward head on the stem and movable relativeto the stem and forward head, a motor spring on the stem actingforwardly against the rearward head, tension means connected with therearward head and extending from said rearward head to have tensionapplied to it, whereby it will cause relative movement of the stem andrearward head against the action of said motor spring, a pair ofrearwardly inclined a ms 9 ea h h a a i pi spring to each head, andoperative connection from the gripping spring to the respective pair ofarms, whereby he gripping spring yieldably presses the arms forward andlaterally outward from their rearward inclinations.

7. In a creeper, a forward head, a stem fixe ther o an ext n ng a ytherefrom, a rearward head on the stem and movable relative to the stemand forward head, a motor spring on the stem acting forwardly againstthe rearward head, tension means connected with the rearward head andextending from, said rearward head to have tension applied to it,whereby it will cause relative movement of the Stem and rearward headagainst the action of said me er Sprin a pa r o arms n e ch h ad,

a gripping spring to each head, operative connection from the grippingspring to the respective pair of arms, whereby the gripping springyieldably presses the arms forward from their rearward inclinations, acollapsing spring to each head, adapted, when released, to compress thegripping spring of the head and to act through the operative connectionto draw the arms backward, means to each head confining these collapsingsprings, and means operated by extra tension on said tension means whileone of the heads is held against travel to release these collapsingsprings.

8. In a creeper, a forward head, a stem fixed thereto and extendingrearwardly therefrom, a rearward head on the stem and movable relativeto the stem and forward head, a motor spring on the stem actingforwardly against the rearward head, tension means connected with therearward head and extending from said rearward head to have tensionapplied to it, whereby it will cause relative movement of the stem andrearward head against the action of said motor spring, gripping means oneach head automatically bearing forwardly to grip, but released whendrawn backward, a safety spring on said stem, receiving the rearwardthrust of the motor spring, connecting means from this safety springforward to the forward head, a collapsing spring in the forward head,and confining means for this collapsing spring, the connecting meansreleasing said confining means on backward movement whereupon saidcollapsing spring draws the gripping means backward and holds it back,said safety spring permitting the connecting means to move backward onlyupon extra tension applied to said cable and after the motor spring hasbeen completely compressed, a movable mounting in the rearward headthrough which the tension means connects with said rearward head,operative connection extending forward from this movable mountin acollapsing spring in the rearward head, confining means for thecollapsing spring, re leased on backward movement of the op era-tireconnection with the movable mounting, whereupon said collapsing springdraws the gripping means back and holds it back, and a safety springholding the movable mounting forward in the head and yielding to allowbackward movement of the movable mounting only upon extra tensionapplied to said tension means.

9. In a creeper, a forward head, a hollow stem fixed thereto andextending rearwardly therefrom, a rearward head movable on said stem, apair of arms to each head, each arm on the head being pivoted at oneside and rearwardly inclined across past the pivoting of the other armon the other side, a toggle head on the stem for each pair of arms, tog-Y 1,12s,7ae

gle links connecting the toggle heads with the respective arms, aforward gripping spring around the stem, a collar fixed on the stemholding this gripping spring to press the forward toggle head forward, arearward gripping spring around the stem, and a frame on said rearwardhead holding this gripping spring to press the rearward toggle headforward, a motor spring around the stem, and means on the stem holdingthis motor spring, to press the rearward head and its fame and the partscarried therewith forward, a pulley rotatably mounted and carried withsaid rearward head and frame, a cable fixed to the stem near its rearend, passing forward around said pulley and baclward, whereby whentension is applied to the cable, it pulls the stem forward through therearward head, compressing said motor spring, and then when tension isreleased on the cable said motor spring pushes said rearward headforward on the stem.

10. In a creeper, a forward head, a stem fixed thereto and extendingrearwardly therefrom, a rearward head movable on said stem, a pair ofarms to each head, each arm on the head being pivoted at one side andrairwardly inclined across past the pivoting of the other arm on theother side, a toggle head on the stem for each pair of arms, togglelinks connecting the toggle heads with the respective arms, a forwardgripping spring around the stem, acollar fixed on the stem holding thisgripping spring to press the forward toggle head forward, a rearwardgripping spring around the stem, and a frame on said rearward readholding this gripping spring to press the rearward toggle head forward,a motor spring around the stem, a safety collar holding said motorspring, but movable on the stem, a safety spring around the stem,holding this collar forward, said stem having a longitudinal slot, anelement on said collar extending through the slot into the stem, a rodinside the stem fixed to this element and extending forward near to theforward head, a collapsing collar around the stem forwardly of theforward toggle head, a collapsing spring confined between saidcollapsing collar and the forward head, said stem having an opening nearthis collar, confining means inside the stem and extending through theopening and engaging said collapsing collar, holding it forward againstthe pressure of the collapsing spring, means on said rod inside the stemholding the confining means outward to thus engage the collapsingcollar, whereby when said rod is drawn backward with the safety collarsaid confining means releases the safety collar and safety spring,allowing them to push the forward toggle head backward, a pulley blockmovable in the frame of the rearward head, a safety spring in said framepressing the pulley block forward, a collapsing collar on the stemforwardly of the rear toggle head, a collapsing spring confined betweenthis collar and the rear head, a yieldable element at the side of theframe confining the collapsing collar and collapsing spring forward fromthe toggle head but releasing them upon yielding outward, allowing themto push the rear toggle head backward, a pulley rotatably mounted on thepulley block, a cable fixed to said stem near its rear end and passingforward around the pulley and rearward, to have tension applied to itand thereby pull the stem forward through the rearward head, compressingsaid motor spring, and then to have tension. released on it, allowingsaid motor spring to push said rearward head forward on the stem, and,upon one of said heads being held against forward movement and extratension being applied to said cable, the respective safety springsyielding as aforesaid.

11. In a creeper, gripping mechanism, comprising a gripping springcausing said mechanism to automatically grip and resist backward motionbut to automatically yield and partake of forward motion, a collapsingspring capable of overpowering the grip ping spring, a safety spring,and means whereby the safety spring confines the collapsing spring butreleases the collapsing spring under extra exertion upon the mechanlsm.

12. In a creeper, gripping mechanism comprising a gripping springwhereby the mechanism automatically grips and resists backward motion,but automatically yields and pal-takes of forward motion, manipulativeengaging means carried with the gripping mechanism, a collapsing springcapable of overpowering the gripping spring, operative connection fromthe manipulative engaging means to the collapsing spring whereby thecollapsing saring is confined, and a safety spring yieldably holding themanipulative engaging means to confine the collapsing spring butyielding under extra exertion upon the manipulative engaging means.

13. In a creeper, gripping mechanism comprising a gripping springwhereby the mechanism automatically grips and resists backward motion,but automatically yields and partakes of forward motion, manipulativeengaging means carried with the gripping mechanism, a collapsing springcapable of overpowering the gripping spring, operative connection fromthe manipulative engaging means to the collapsing spring whereby thecollapsing spring is confined, a safety spring yieldably holding themanipulative engaging means to confine the collapsing spring butyielding under extra exertion upon the manipulative engaging means, andmeans for adjusting the resistance of said safety spring.

14:. In a creeper, a forward gripping mechanism, a rearward grippingmecha nism, each of said mechanisms automatically gripping and resistingbackward movement but automatically yielding and partaking of forwardmovement, manipulative engaging means carried with the rearwardmechanism, manipulative means connected to the forward mechanism andengaging with the manipulative engaging means 'whereby the forwardmechanism may be moved forward relative to the rearward mechanism, amotor spring compressed during this forward movement and afterwardexpanding to move the rearward mechanism forward relative to the forwardmechanism, collapsing means for each mechanism, and a safety spring toeach mechanism normally holding the collapsing means inoperative butyielding and allowing the collapsing means to operate under extraexertion upon the manipulative means.

15. In a creeper, a forward gripping mechanism, a rearward grippingmechanism, each of said mechanisms automatically gripping and resistingbackward movement but automatically yielding and partaking of forwardmovement, manipulative engaging means carried with the rearwardmechanism, manipulative means connected to the forward mechanism andengaging with the manipulative engaging means whereby the forwardmechanism may be moved for ward relative to the rearward mechanism, amotor spring compressed during this forward movement and afterwardexpanding to move the rearward mechanism forward relative to the forwardmechanism, collapsing means for each mechanism, the manipulativeengaging means of the rearward mechanism being movable relative to saidrearward mechanism, operative connection from this movable manipulativeengaging means to the collapsing means to confine the collapsing means,a safety spring carried with the rearward mechanism normally holding themanipulative engaging means to confine the collapsing means, butyielding either upon the forward gripping means being obstructed or uponcomplete compression of the motor spring by extreme advance of theforward gripping means, a safety spring carried with the forwardgripping means, means carried with the forward gripping means foroperatively engaging with the motor spring, this means being movable andnormally held toward the motor spring by the safety spring of thisforward gripping mechanism, operative connection from this operativeengaging means to the collapsing means of the forward grippingmechanism, this safety spring of this mechanism yielding whereby thecollapsing means of the mechanism is released upon the completecompression of said motor spring, either by extreme advance of theforward mechanism or extreme retraction of the rearward mechanism.

FRED N. BIERCE.

Witnesses:

CLARENCE Pnnnnw, JAMES N. RAMsEY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, I). G.

